This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A070915 #21 Mar 10 2024 09:32:40 %S A070915 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26, %T A070915 27,28,29,31,32,33,34,35,36,37,38,39,40,41,43,44,45,46,47,48,49,50,51, %U A070915 52,53,54,55,56,57,58,59,61,62,63,64,65,67,68,69,71 %N A070915 Numbers having at most two distinct prime factors. %H A070915 G. C. Greubel, <a href="/A070915/b070915.txt">Table of n, a(n) for n = 1..10000</a> %F A070915 A001221(a(n)) <= 2. %F A070915 a(n) ~ n log n/log log n. - _Charles R Greathouse IV_, Oct 16 2015 %e A070915 88 and 77 are terms, as 88=11*2^3 and 77=11*7, but 66 is not a term, as 66 = 11*3*2. %t A070915 Select[Range[80],PrimeNu[#]<3&] (* _Harvey P. Dale_, Sep 19 2012 *) %o A070915 (PARI) is(n)=omega(n)<3 \\ _Charles R Greathouse IV_, Oct 16 2015 %Y A070915 Disjoint union of A000961 and A007774. %Y A070915 A003586 is a subsequence. %Y A070915 Cf. A001221. %Y A070915 Complement of A000977. %K A070915 nonn %O A070915 1,2 %A A070915 _Reinhard Zumkeller_, May 20 2002